Understanding Barcodes and Barcode Technology.

Typical 1D Barcode
(Symbology EAN 128A)

A barcode is an optical machine-readable representation of data, which shows data about the object to which it attaches. Originally, barcodes represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or 1 dimensional (1D).

Different types of barcodes currently available.

A Barcode Symbology defines the technical details of a particular type of barcode: the width of the bars, character set, encoding method, checksum specifications, etc. Mostly we are more interested in the general capabilities of a particular type of barcode symbology (how much and what kind of data can it hold, what are its common uses, etc) than in the technical details.

They are 2 distinct types of barcode currently available: the linear barcode type and the 2D barcodes. Using the right barcode depends on the environment, requirements, applications and printers.

Linear Barcode Symbologies

They are a large list of 1D linear barcode symbologies in use across the world today, the most common types are :-

UPC

Universal Product Code - The UPC has only numerals, with no letters or other characters.

Codabar

It was designed to be accurately read even when printed on dot-matrix printers

Code 39

The barcode itself does not contain a check digit, but it can be considered self-checking on the grounds that a single erroneously interpreted bar cannot generate another valid character.

Code 128

This is a very high-density barcode symbology. (A special version of it called GS1-128 is used extensively world wide in shipping and packaging industries.) It is used for alphanumeric or numeric-only barcodes. It can encode all 128 characters of ASCII

EAN 8 /13

European Article Number (Now called - International Article Number). All the numbers encoded in EAN barcodes are known as Global Trade Item Numbers (GTIN), and they can be encoded in other GS1 barcodes.

2D Barcode Symbologies

A matrix code, also known as a 2D barcode or simply a 2D code, is a two-dimensional way of representing information. It is similar to a linear (1-dimensional) barcode, but has the ability to contain a lot more data. Introduced in the 1990's as a replacement of the standard 1D linear barcode. 2D barcodes can use upper and lower case letters, numerical symbols and special characters all packed in very small compact area. The data present in this compressed format is read very quickly and easily by a digital device.

Data Matrix

Data Matrix are a two-dimensional barcode consisting of black and white "cells" or modules arranged in either a square or rectangular pattern.

PDF417

The PDF417 bar code (also called a symbol) consists of 3 to 90 rows, each of which is like a small linear bar code. They can link to other symbols which are scanned in sequence allowing even more data to be stored

Maxicode

A MaxiCode symbol (internally called 'Bird's Eye', 'Target', or 'ups code') appears as a 1 inch square, with a bullseye in the middle, surrounded by a pattern of hexagonal dots.